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27 April 2009 Phage-based magnetoelastic biosensor for the detection of Salmonella typhimurium
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In this paper, we report a wireless magnetoelastic (ME) biosensor with phage as the bio-recognition probe for real time detection of Salmonella typhimurium. The ME biosensor was constructed by immobilizing filamentous phage that specifically binds with S. typhimurium onto the surface of a strip-shaped ME particle. The ME sensor oscillates with a characteristic resonance frequency when subjected to a time varying magnetic field. Binding between the phage and antigen (bacteria) causes a shift in the sensor's resonance frequency. Sensors with different dimensions were exposed to various known concentrations of S. typhimurium ranging from 5 x101 to 5 x 108 cfu/ml. The detection limit of the ME sensors was found to improve as the size of the sensor became smaller. The detection limit was found to improve from 161 Hz/decade (2mm length sensors) to 1150 Hz/decade (500 μm length sensors). The stability of the ME biosensor was investigated by storing the sensor at different temperatures (25, 45, and 65 °C), and then evaluating the binding activity of the stored biosensor after exposure to S. typhimurium solution (5 x 108 cfu/ml). The results showed that the phage-coated biosensor is robust. Even after storage in excess of 60 days at 65 °C, the phage-coated sensors have a greater binding affinity than the best antibody coated sensors stored for 1 day at 45 °C. The antibody coated sensors showed near zero binding affinity after 3 days of storage at 65 °C.
© (2009) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Suiqiong Li, Ramji S. Lakshmanan, Rajesh Guntupalli, Shichu Huang, Z.-Y. Cheng, Valery A. Petrenko, James M. Barbaree, Vitaly Vodyanoy, and Bryan A. Chin "Phage-based magnetoelastic biosensor for the detection of Salmonella typhimurium", Proc. SPIE 7315, Sensing for Agriculture and Food Quality and Safety, 731503 (27 April 2009);

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